webvideo-clip-core/src/video-types/youtube/clipper.ts

import { spawnSync } from 'child_process';
import { readFileSync, unlinkSync } from 'fs';
import {
  ClipVideoParams as BaseClipVideoParams,
  CreateClipperParams as CreateBaseClipperParams,
  FILE_TYPES,
} from '../../common';
import { VIDEO_TYPE } from './common';
import { constructDefaultDownloadArgs, getFileExtension } from './downloader';
import { DownloaderFailedToStartError, DownloaderNotFoundError } from './errors';
import {retrieveVideoId} from './url';

export interface CreateClipperParams extends CreateBaseClipperParams {
  type: typeof VIDEO_TYPE;
}

export interface ClipVideoParams extends BaseClipVideoParams {}

export const createVideoClipper = (createClipperParams: Omit<CreateClipperParams, 'type'>) => (clipVideoParams: ClipVideoParams) => {
  if (!createClipperParams.downloaderExecutablePath) {
    throw new DownloaderNotFoundError('Downloader not found.');
  }

  const fileExtension = getFileExtension(
    createClipperParams.downloaderExecutablePath,
    clipVideoParams.url,
  );
  const videoId = retrieveVideoId(clipVideoParams.url);
  const cacheFilename = `output.${encodeURIComponent(videoId)}.${fileExtension}`;
  const downloadArgs = constructDefaultDownloadArgs(
    cacheFilename,
    clipVideoParams.url,
    clipVideoParams.start,
    clipVideoParams.end,
  );
  const downloaderProcess = spawnSync(
    createClipperParams.downloaderExecutablePath,
    downloadArgs,
  );
  if (downloaderProcess.error) {
    throw new DownloaderFailedToStartError('Downloader failed to start.', { cause: downloaderProcess.error });
  }
  const output = readFileSync(cacheFilename);
  unlinkSync(cacheFilename);
  return Promise.resolve({
    contentType: FILE_TYPES[fileExtension],
    content: output,
  });
}